/* istanbul ignore next */
const trim = function(s) {
    return (s || '').replace(/^[\s\uFEFF]+|[\s\uFEFF]+$/g, '')
  }
  
  /* istanbul ignore next */
  export function hasClass(el, cls) {
    if (!el || !cls) return false
    if (cls.indexOf(' ') !== -1)
      throw new Error('className should not contain space.')
    if (el.classList) {
      return el.classList.contains(cls)
    } else {
      return (' ' + el.className + ' ').indexOf(' ' + cls + ' ') > -1
    }
  }
  
  /* istanbul ignore next */
  export function addClass(el, cls) {
    if (!el) return
    let curClass = el.className
    const classes = (cls || '').split(' ')
  
    for (let i = 0, j = classes.length; i < j; i++) {
      const clsName = classes[i]
      if (!clsName) continue
  
      if (el.classList) {
        el.classList.add(clsName)
      } else if (!hasClass(el, clsName)) {
        curClass += ' ' + clsName
      }
    }
    if (!el.classList) {
      el.className = curClass
    }
  }
  
  /* istanbul ignore next */
  export function removeClass(el, cls) {
    if (!el || !cls) return
    const classes = cls.split(' ')
    let curClass = ' ' + el.className + ' '
  
    for (let i = 0, j = classes.length; i < j; i++) {
      const clsName = classes[i]
      if (!clsName) continue
  
      if (el.classList) {
        el.classList.remove(clsName)
      } else if (hasClass(el, clsName)) {
        curClass = curClass.replace(' ' + clsName + ' ', ' ')
      }
    }
    if (!el.classList) {
      el.className = trim(curClass)
    }
  }
  